QT interval dispersion and cardiac sympathovagal balance shift in rats with acute ethanol withdrawal.
QT interval dispersion and cardiac sympathovagal balance shift in rats with acute ethanol withdrawal.
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DOI：
10.1111/j.1530-0277.2009.01085.x
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发表时间：
2010-02
期刊：
影响因子：
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通讯作者：
Seiko Shirafuji;Jinyao Liu;N. Okamura;K. Hamada;T. Fujimiya
中科院分区：
文献类型：
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作者：
Seiko Shirafuji;Jinyao Liu;N. Okamura;K. Hamada;T. Fujimiya
背景自主神经功能失调和心肌复极均一性受损是非酒精性室性心律失常发生的两个重要机制。我们以前的研究表明，急性乙醇戒断促进心脏交感迷走神经平衡向交感神经优势的转变，并降低迷走神经张力，这与室性心律失常和相关死亡的发生率较高有关。然而，心肌复极的均匀性及其与心脏交感迷走神经平衡的关系尚不清楚，尤其是在酒精中毒的受试者中。本研究报告的目的是澄清这些问题。方法雄性Wistar大鼠连续灌胃乙醇49 d，停药1 d，停药1 d后给予卡维地洛（可通过β 1、β 2和α肾上腺素能受体完全阻断交感神经系统）预处理7 d。根据心率变异性（HRV）和QT间期离散度（QTd：QT间期的动态变化）评价心脏交感迷走神经平衡和心肌复极均匀性。结果卡维地洛预处理组大鼠在停药后1d出现QTd延长，而非酒精性、持续性乙醇摄入组及停药后1d未出现QTd延长。停药1 d时，HRV的低频/高频功率（LF/HF）比值升高，且与QTd相关。大鼠在乙醇戒断1天后接受7天卡维地洛预处理，QT离散度增加和LF/HF比值升高恢复正常。结论：突然终止慢性持续乙醇摄入大鼠，心肌复极的均一性受损，并与心脏交感迷走神经平衡相关。卡维地洛预处理与QTd和LF/HF比值的降低相关，增加了心脏交感迷走神经平衡偏移可能是心肌复极均匀性受损的原因，β受体阻滞剂预处理可能降低酒精戒断期间的死亡风险。
BACKGROUND Dysregulation of autonomic nervous system function and impaired homogeneity of myocardial repolarization are 2 important mechanisms for the genesis of ventricular arrhythmias in nonalcoholic subjects. Our previous study suggested that acute ethanol withdrawal promoted the shift of cardiac sympathovagal balance toward sympathetic predominance and reduced the vagal tone, which were related to a higher incidence of ventricular arrhythmia and related death. However, the homogeneity of myocardial repolarization and its relation with the cardiac sympathovagal balance are unknown, especially in alcoholic subjects. The aim of the present study was to clarify these points. METHODS Male Wistar rats were treated with a continuous ethanol liquid diet for 49 days, and then subjected to 1-day withdrawal and 1-day withdrawal with 7-day carvedilol (can block the sympathetic nervous system completely via beta1, beta2, and alpha adrenergic receptors) pretreatment. The cardiac sympathovagal balance and homogeneity of myocardial repolarization were evaluated based on the heart rate variability (HRV) and QT interval dispersion (QTd: dynamic changes in QT interval duration). RESULTS The increase in QTd was observed only in rats at 1-day withdrawal, but not in nonalcoholic, continuous ethanol intake, and 1-day withdrawal with 7-day carvedilol pretreatment rats. At 1-day withdrawal, the low-frequency power/high-frequency power (LF/HF) ratio in HRV was elevated and correlated with the QTd. The increased QTd and elevated LF/HF ratio were normalized by the 7-day carvedilol pretreatment in rats at 1-day ethanol withdrawal. CONCLUSIONS In rats with an abrupt termination of the chronic continuous ethanol intake, the homogeneity of myocardial repolarization impaired and correlated with the cardiac sympathovagal balance. Carvedilol pretreatment is associated with a reduction in both the QTd and LF/HF ratio, raising the possibility that the cardiac sympathovagal balance shift may be responsible for the impaired homogeneity of myocardial repolarization, and that beta-blocker pretreatment may decrease the mortality risk during alcoholic withdrawal.